code: def preload(self):
      try:
          self.next_input, self.next_target = next(self.loaditer)
      except StopIteration:
          self.next_input = None
          self.next_target = None
          return
      with ch.cuda.stream(self.stream):
          self.next_input = self.next_input.cuda(non_blocking=True)
          self.next_target = self.next_target.cuda(non_blocking=True)
  
imports: import torch
  import shutil
  import dill
  import os
  from subprocess import Popen, PIPE
  import pandas
  from PIL import Image
  from .None import constants
label_desc: Use image node_id 3 for calling the DataPrefetcher obj's underlying member method code with example usage: obj.preload() without return types